OK. You are 16! In this case, simply stick with it. You will rapidly become strong enough to tackle whatever lies beneath your tires... just remember that the faster your feet move as you pedal, the less force they have to exert as they pedal. I had a sadistic gym teacher who taught me to switch to the harder-to-pedal gears as I went uphill... he was wrong and stupid. Mechanical advantage is no sin - as small a front gear as you can manage, with as big a rear gear, and you'll zip up the steepest of hills. Soon you'll have a buff body, and the jocks will gnash their teeth-guards with envy as the cool, smart girls will be all-up-ons a hard-core cyclist.